1.28 Ct. Spinel

This transparent purplish grey spinel, weighing 1.28 carat, presents a precise trillion shape with finished dimensions of 6.98 by 7.07 by 4.41 mm. Evaluated at eye level the clarity is eye clean, and the medium color intensity sits in a neutral to slightly violet plane that balances tone and saturation. The stone is unenhanced, with an excellent polish and carefully executed facet junctions. From a material properties perspective, spinel is isometric and optically isotropic, with a refractive index in the range associated with strong light return, high surface lustre, and no birefringence, which contributes to uniform optical behaviour under faceted cutting. The depth translates to an effective pavilion proportion of approximately 62.8 percent relative to the average girdle width, a proportion that supports efficient internal reflection without the overly deep dark zones that can reduce apparent size. Origin is recorded as unknown, which makes the untreated nature of this specimen particularly relevant for connoisseurs who prioritize natural state and stable coloration.

The trillion cut on this piece has been executed to emphasize triangular symmetry and to maximize both scintillation and broad flash phenomena typical of well cut triangular brilliants. The cutter has used a modified triangular brilliant facet layout on the crown combined with a multi facet pavilion configuration, producing a pronounced central star and clean triangular periphery when viewed face up. The excellent polish enhances facet crispness and minimizes surface scattering, allowing the internal facet geometry to govern light behaviour. Because spinel is isotropic, the cutter can rely on consistent light paths across all facets, permitting slightly more aggressive crown and pavilion angles tuned to the material refractive index to enhance return and contrast. The result is a balanced presentation where white light return is strong, contrast is controlled, and flash sizes vary from small scintillation points to larger flashes depending on viewing distance and light source. Eye clean clarity means these optical effects are uninterrupted by inclusions, yielding a transparent, lively appearance that reads larger than its carat weight would suggest.

In direct comparison to more common gemstones, this purplish grey spinel stands apart in several technical ways. Compared to diamond, spinel has a lower refractive index and lower dispersion, so it does not exhibit diamond style fire, however it benefits from exceptional transparency and a clean medium tone that allow larger coherent white light flashes and a satin like brilliance that is more calming and expansive than the more fragmented brilliance in some lower clarity stones. Against corundum varieties such as sapphire, which often possess strong pleochroism and deeper saturation that can absorb light and reduce apparent brightness, this spinel’s isotropic nature and medium intensity permit greater uniformity of colour and more efficient light transmission, producing a perceived brightness comparable to or higher than many coloured stones of similar size. Versus stones known for strong colour shifting such as tanzanite, the spinel offers predictable colour in all orientations, which is advantageous for design stability and predictable mounting. The purplish grey hue is neutral enough to integrate with both white and warm metals, yet it maintains a distinctive violet undertone that reveals itself under incandescent illumination, offering a dual personality between cool natural daylight and warm interior lighting.

This specimen from The Natural Gemstone Company will appeal to gem collectors, precision cutters, and designers who appreciate the interaction between material constants and cut geometry, and who value unenhanced provenance and excellent polish. For setting considerations, the stone’s triangular outline and the calculated pavilion depth make it ideal for three prong or secure V prong mounts that preserve the faceted perimeter and maximize visible table area. For buyers seeking further technical documentation, we can provide additional high resolution imagery and gemological commentary on request, enabling precise evaluation for bespoke settings or investment grade acquisition.